This term goes back to James Davies' Life and Death and clarifies what one means by alive. Divide groups into three kinds:
When determining the status of a group, we always assume alternating play. This is as simple as it can be. Complications are introduced by ko.
Some tsumego problems ask one to determine the status of a group. Analogously to the list above, the answer will be one of three kinds:
Velobici: Status problems have a distinct advantage over all other types of life and death problems. One must determine whether or not an additional move is required to settle the inside group. This is exactly the same skill that one is required to exercise repeatedly while playing. Therefore, status problems can be the most rewarding in actual play.